Torsional oscillation generator



1948- R. B. ALLNUTT El AL TORSIONAL OSCILLATION GENERATOR Filed Aug. 8, 1946 AW. M R? OM H 640 mm: mm

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.wil1 be apparent during Patented Oct. 26, 1948 TQRSIONAL OSCILLATION GENERATOR n Echo Heights, Mai, and

Ralph B. Allnutt, Gle

Raymond'l. McGoldrick,

Brooklyn, N. Y.

.Application August 8,1946 Serial No. 689,131

3 Claims.

(Granted under the act ct -March 3, 1883, has

amended April 30, 1928; -1 ?l(l,O.,(3r. 757) .;1 'iThe invention relates .to improvements in equipment for. generating. torsional vibrations in rotating .shafts,;and; morespecifically to a tor- .sional vibration generator particularly well adapted for .use in. calibrating various forms of .torsiographs such, as disclosed in Patents ,2,219,298;L.2,25l,'l72; and 2,399,635 granted to .Dashefsky,. Draper and. Hope, respectively.

.fIheprimary, objectof the invention is the provisionpfiaitorsional oscillation generator having meansfor. independently varying the amplitude and frequency-of the, torsional oscillations, as Well :asthe shaft speed, while the machine is in motion.

. Another object ofthe invention is the provision ofa torsional oscillation generator havin means for controlling the. frequency of oscillations independent of the shaft speed.

Afurtherobject is to provide a torsional oscillation generator having means for adjusting the amplitude-of oscillationsindependent of the shaft speed.

A still further objectistohproyide a torsional oscillationeggenerator having means for varying the frequency and amplitude of oscillations independent of the shaft speed.

The invention also aims to providea torsional oscillation generator having means for'determining and adjusting the amplitude of the oscillations.

Additionally, the invention;.is directed toward the provision of a torsionaloscillation generator whichis constructed chiefly from commercially available parts.

Other objects and advantages of the invention ing detailed'description, taken in connection with the accompanying drawing, forming a part of this specification, and in which drawing,

Figure 1 is a side elevational view of the torsional oscillation generator with parts thereof broken away and shown in central vertical section.

Figure 2 is a fragmentary top plan view of a pump and hydraulic connections preferably forming part of the oscillation generator.

Figure 3 is a fragmentary detail view, partly in side elevation and partly in central vertical section, of a rotary pipe coupling preferably forming part of the oscillation generator.

Figure 4 is a central vertical cross-sectional view of the oscillation generator, substantially on the line 4-4 of Figure 1.

In the drawing, which for the purpose of illustration shows only a preferred embodiment of the invention, and wherein similar reference thecourse of the followby a"-"l' r2. forming part of. the

and pipe 2'5, to the T '22. in the housing 25, as

characters denote corresponding parts throughout the views, in generally designates the. tor sional oscillation generator which may include a Waterbury variable stroke pump l I such as disclosed in U. S. Patent 2,168,658, granted on the invention. of W. Thomas. Briefly, the Waterbu y variable stroke pump is .a reciprocating piston pump of the parallel rotary cylinder type provided withra-control shaft 12 turnable as by a handwheel J3 to vary the piston stroke and thus the quantity of. fluid delivered. If a conventional eeven-piston Waterbury pump produces a flow of oil that is substantially continuous, it will be necessary to use: apumphavingifewer pistons so that distinct and substantially independent rather than smoothly overlapping;impulseswill be produced.

.Operatively connected tozthe pump H as by, a

shaftcoupling M is a variable speedmotor l5 supportedwiththe pump N 011 3. commonbaseplate It. Connecting the outletand inlet ports ll, 18 .of the pump is a hydraulic conduit l9 providedwith a-control valve 2!] for regulating the oil pressure in the conduit. The mean static pressure produced by the pump I i may be measuredxby a-suitable static pressuregage 2I'carried conduit l9. Also carried bythe T is a suitable'dynamicpressure gage-.23 which 1 may be of the diaphragm type shown in,U.- S. Patent 2,360 886, granted to Osterberg.

zMoun-ted on the baseplate 16 is a rotary pipe coupling-2d including a cylindrical housing 25 connected at one end, as by a removable cap 26 Rotatably supported by spacedbearings 28-, 29, is one end portion of a shaft 3%} having an axial passageway 3i communicating with the pipe 21. The shaft til is provided with a series of spaced annular ribs 32 closely fitting in spaced annular grooves 33 internally of the cylindrical housing 25 whereby a labyrinth is formed in the space between the housing and shaft tending to prevent the escape of oil from the housing. Externally of the housing 25 and shaft (it is supported in spaced bearings s4, 35 for rotation by a variable speed electric motor 35 through a flexible V-belt 3? and pulleys 38, 39. The belt drive tends to prevent transmission of torsional vibrations between the shaft 30 and the motor 35.

Fixed to the shaft 30 between the spaced bearlugs 34, 35 at an integral annular flange 40, as by bolts 5!, is a supporting member or flywheel 32 provided with opposite substantially sectorshaped openings d3, 44. Additional openings 45,

46 may be provided for balancing, if necessary. Mounted for oscillation on the shaft, as by a hub 41 and bushing 48, are diametrically opposite arms 49, 56 disposed within the sector-shaped openings 43, 44 and provided at their free outer ends with weights 5!, 52. Interposed between the weights BI, 52 and the sidewalls of the sector-shaped openings 43, 44 are compression coil springs 53, 54, 55, 56, urging the weights toward the centers of the openings 43, 44. Communicating with the end portion of the axial passageway 3|, which terminates adjacent the zone of connection of the flywheel and shaft, are tubes 51, 58 that extend radially outward from the shaft 30 and supply oil to suitable flywheel ducts 59, 60 leading into expansible bellows 6|, 62. posed between the flywheel and arms 49, 50 so that expansion of the bellows will unbalance springs 53, 54, 55, 56 and thus displace the arms and weights BI, 52 in a counter-clockwise direction as Viewed in Figure 4.

An adapter 33 is fastened to the outer end of the shaft 36 for connection to any selected torsiograph to be calibrated.

During operation of the universal torsional calibrator, successive impulses produced by the variable stroke pump will be transmitted through the shaft passageway 3|, tubes 51, 58 and ducts 59, 68 to the bellows 6|, 62 so as to efiect oscillation of the weights SI, 52 near the outer periphery of the flywheel thus producing torsional oscillations of the shaft. The speed of the torsion shaft 30 may be adjusted by varying the speed of the electric motor 36; the frequency of torsional sci11ations generated in the shaft may be adjusted by varying the speed of the pum motor l; and the amplitude of oscillations generated may be varied by adjusting the stroke of the pump II by rotation of the control shaft handwheel IS. The mean static pressure of oil in the conduit I9 as indicated by gage 2| will depend on the setting of control valve 26 and on the operating speed and stroke of the pump H. Thus adjustments for any combination of shaft speed, torsional vibration frequency, and amplitude can be made while the machine is in motion. Any selected torsiograph connected to the adapter 63 may be subjected to torsional vibrations of various known frequencies and amplitudes at which the torsiograph is to be calibrated, the frequency and amplitude of torsional vibration at any moment being indicated by the dynamic pressure gage, whereby the torsiograph may be calibrated or checked under known conditions.

The bellows 6|, 62 provide a certain amount of dampingbetween the flywheel 42 and arms 49, 50.

These bellows are dis- If desired, additional damping between the f wheel and arms 49, 5t may be provided to more: the frequency range of the calibrator.

Various changes may be made in the form invention herein shown and described witho departing from the spirit of the invention or t scope of the following claims.

The invention described herein may be man factured and used by or for the Government the United States of America for government purposes without the payment of any royalti thereon or therefor.

We claim:

1. In a torsional oscillation generator a drive shaft, a flywheel element, a weight element, or of said elements being fastened to the shaft, tt other of said elements being mounted for oscille tion relative to the first-mentioned one, mear rotating the shaft at any selected speed, a hy draulic motor for oscillating the weight relativ to the flywheel, a variable displacement pum havin its output connected to said motor, an means operating the pump at any selected speec 2. In a torsional oscillation generator, a drive: shaft having an axial passageway, a variable dis placement hydraulic pump, means supplying sail shaft passageway with hydraulic fluid from sail pump, a flywheel element, a weight element, on of said elements being fastened to the shaft, th other of said elements being mounted for oscillation relative to the first-mentioned one, meam rotating the shaft at any selected speed, a hydraulic motor for oscillating the weight relativr to the flywheel, a conduit for transmitting fluic pressure from said shaft passageway to said bydraulic motor, and means operating the pump at any selected speed,

3. In a torsional oscillation generator as specified in claim 2, means for measuring the instantaneous hydraulic pressure supplied by said pump to said driven shaft.

RALPH B. ALLNUTT. RAYMOND T. McGO-LDRICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,531,563 McDowell Mar. 31, 1925 1,610,487 Brinton Dec. 14, 1926 1,677,884 Connelly July 24, 1928 2,069,271 Prescott Feb. 2, 1937 2,384,987 Dudley Sept. 18, 1945 

